Tuesday, June 01, 2010

So dear readers, quick recap : there's this idea floating around of Swiss rider Fabian Cancellara using an electric motor at the classics. It seems to have originated at the rumor mills of il Italia and a couple of journalists, an ex-pro cyclist and a little known e-bike maker are in the thick of it. Meanwhile, Fabian tossed out a statement today in the press calling hogwash to these claims. Hey, the truth is out there...

Last evening, I spent some time re-watching 2010 Paris Roubaix clips. My focus was upon the attack from Cancellara with 48k to go. To me, there were three segments to this attack :

"..can we dissect this attack and see its parts to get a perspective of what's happening?"

2) In the next 2 or 3K, the group splintered. Leif Hoste, Björn Leukemans, Frederic Guesdon and Sébastien Hinault pushed to the front.

3) At 49 K to go, Fabian Cancellara surged ahead from the bunch to join the four leaders. In a few seconds, he took one sideways look behind him, saw that the title defender Boonen had decided not to mark him down. Riis, the team manager, radioed to him. "Go". Yup, it was a bad move from the Belgian champion. Fabian was then gone and the rest is history.

The jump Fabian put forth was strong and decisive. To most of us, watching the surge (see video below) may seem almost like, well, like he had a motor somewhere on the bike. How on earth can he pull away so quick, right? Well the Italians asked that hard question and came up with the answer - 'Oh mio dio, he has a motor on his bike!'

But regardless of whether he used a motor or not, can we dissect this attack and see its parts to get a perspective of what's happening? I think we could.

So I used a physics analysis software and some basic physics to get an idea of the speed and acceleration involved in this attack. This may seem pretty ghetto to some of you but perspective is what ultimately matters.

STEPS

1) First, I downloaded the above video of the action from Youtube. I cut the video segment only to the points of interest, from 2:07 to 2:22 or so. I eventually a few hundred frames at 25 frames/second. I decided a timestep of about 0.03-0.04 seconds would be more than adequate to the capture the stages of the action.

2) I scaled the segment with a known dimension of some entity. That entity was going to be Cancellara's 58cm Specialized bike. I looked up its specs and found out that the wheelbase of the frame is pretty close to 100 cm or 1m. Good enough.

3) I imagined myself seated inside the TV helicopter, shining a path co-ordinate axis down at the action below, somewhere in the middle of the screen. I reckoned that the zoom and pan from the helicopter camera would create complexities, but luckily for me, there was not much. The cameraman in the helicopter had kept his focus remarkably steady on the racers, without much shaking and distraction. There was a bit, but I knew exactly where it was. Then I positioned the axis angle to be somewhat parallel to the direction of motion on the road.

4) I then stuck point mass trackers on Fabian, spectators and motorcycles. These trackers would give me position vs time information of the object as the cross-hairs of the camera sped past them.

I finally had distance vs time plots from objects to plug into MS Excel. Since velocity depends on the observer, and since the observer is in a moving state in a helicopter, any relative motion between the observer and the cyclists is either a surge or a deceleration.

Let's explore the stages of the attack :

A) At what speed was the peloton with favorites moving initially?

Here, helicopter camera was very focused on the action with little shaking. Hence, a spectator appearing and flying out of view may give an indication of the speed of the riders. The position time graph was a straight line. The data was exported in Excel and a "linest" operation on the data yielded a slope, as shown below.

25 mph is not hard to believe.

B) What was the speed of the lead group that surged away?

Here's another spectator! Let's catch him!! So we place a tracker on his bosom.

This is how fast he flies away from the camera. The slope tells me 29mph. Hence, the leaders broke off with an extra 4 mph relative to the peloton.

C) The attack : How fast can Fabian put a 5 second gap on others?

This pic shows a tracker placed on Fabian, and the graph shows his position changing wrt to the origin due to relative motion. This relative motion is the attack!

Fabian was to the right of camera's origin (purple axis) before he attacked. The camera was focused on the lead group and did not follow Cancellara when he attacked due to the "lag" in reaction time from the cameraman. The downward slope on this graph indicates Cancellara moving towards the negative left side of the origin with his surge. In a little over 4 seconds, the brunt of the attack came, when the slope of the graph dips further, indicating acceleration. The area of interest is limited to 12 seconds because the cameraman suddenly finds out what's happening and shifts his focus to Fabian. This is why the red line begins to curve back up again.

So I exported that graph into Excel, inverted the graph so I would get nice positive numbers. Then I cut the graph to the area of interest.

Presto! This shows us that Fabian puts in a 5" gap very quickly. But how quick is "quickly"?

...this gives us an idea of Fabian's relative speed from the camera focus. So what happens in this 5" gap that Fabian puts relative to peloton? In the first 2 seconds, he manages +1.6 mph. In the next half second or so, he increases that to +3.3 mph, which then bumps up to +6.5 mph until at the second before the camera catches up with Fabian, he's riding at an impressive +7.4mph.

Since I wrote before that camera's focus was traveling at 29mph, this means that the Fabian's respective speeds are 30.6 mph (49.2kph), 32.3 mph (52.3kph), 35.5 mph (57kph) and finally 36.4 mph (58.5kph). This corresponds to an acceleration of around 0.7-0.9 m/sec^2. Ordinary cars have an acceleration of 3-4 m/sec^2. Fabian musters close to 25% of a car's acceleration. Vroom!

D) A reality check :

I stuck a tracker on a passing motorcycle as it sped past Cancellara to "get out of the way". Perhaps it was Graham Watson in the back seat as the flashes of a camera went off. Nevertheless, I found it had a relative speed of +25mph from similar analysis. Adding this to Cancellara's speed of 29mph gives a roundabout motorcycle speed of 60mph (96kph). Its believable.

Also, if I were to plug in the speed I obtained and Cancellara's weight and cadence into Analytic Cycling's "Forces on Rider" calculator (with generic parameters), it gives me about 680 Watts of power. Still believable by STATIC riding standards.

But since I said that he's accelerating with 0.9m/s, given a weight total weight of 87kg (80 kg Fabian and 7 kg bike) and a final speed of 16m/s, we should really calculate his power output and crank torque in a dynamic situation. For the crucial 5 seconds of attack time, I calculate all those below.

I assume Fabian was on his 53-11 gear, which I'm sure he could easily pedal.

Onto the propulsive force required.

Work done then becomes :

So what is his power output to accelerate for those first 5 seconds?

Though not very relevant, also notice that this power output equates to a rough 5 sec power to weight ratio of 1200W /80kg = 15 which is nothing out of the ordinary based on a power to weight ratio chart for male cyclists (See Power to Weight Ratio).

Using a stopwatch, I figured Cancellara increased his RPM from his previous 100 to 110 RPM for his attack. The average torque required for this acceleration at the crank is then :

That value is within the realm of competitive cycling. Since I said this is an average, it would be the average of the "sine-curve" of torque on the y-axis and crank angle on the x axis. The crank torque is scaled down at the rear wheel by a factor of the gear ratio, calculated earlier, since it rotates faster.

For readers on both side of the Atlantic Ocean, I put this all together in one table with units :

My sanity check is over. The numbers are believable by DYNAMIC riding standards. Any doubt? Note that some data from the recent Tour of Flanders indicates that he put in 1450 Watts during the attack on the Muur. That number came after a very long day of riding. If he can manage that, he can surely manage 1200 Watts in the initial moments of his breakaway.
This is my two cents.

CONCLUSION

It is the first 5-10 seconds of an attack that is most crucial and most tricky. Attackers must be able to speed off from an already high pace, and the objective is to dig in to hell, gather the firepower and deliver the maximum blow without suicide.

It is the rapid rate at which Fabian Cancellara increases his speed that is mind boggling to see in the video, even though such speeds are pretty normal for him.

Don't get hung up on the numbers presented here, which is all approximate. But we know from historical data that Fabian is someone who can out-sprint the best by simply staying seated on his saddle, even after 230K of racing. The following is one of those spectacular moments of Tour de France history that will not erode away with time. Watch :

680watts for Cancellara whose race weight is reportedly 75-80 kg means 8.5-9 watts/kg. It's nothing to speak of for a rider of his caliber, unless he sustained that kind of output level for more than a couple of minutes.

I know from writing about Fabian that his 5 min power to weight ratio is about 7.6. Do the math, he can easily sustain an absolute 600 watts for 5 minutes, atleast in 2008. In an attack, that's all you need as an advantage, while the rest try to hold onto him for dear life. You should have seen the grimace on one rider as he tried to stick with Cancellara in the break on the PR cobbles. Its apparent he started yelling to him to slow down. Either that or he yelled at the photo crew on the motorbike but highly unlikely given the distance.

Genetically speaking, Cancellara is one of those freak behemoths in the peloton. The cross section of muscle fiber he has in those legs could be substantial for power delivery. His fingers are the size of your head. He uses 177mm cranks...lots more.

In sports, freaks get ahead of their game. It has everything to do with their bodies and little with the bike or related technology. Someone who starting accusing him of using a motor hasn't realized this yet.

You used the wrong calculator on Analytic Cycling - that is the power to do 16m/s steady state not an acceleration from 13 to 16m/s in ~10 seconds. Actual power would be nearer to 940W with the same assumtpions on CdA and weight.

I heard Magnus Backstedt speaking about the power he put out during a previous P-R. He said it was equivalent to his 4k pursuit power for each of the cobbled sections, with it being in excess of 1000 watts (more than 1200 in some instances.

Granted Maggy outweighs Cancellara, and I don't know how accurate his power meter was (particularly on cobbles), but I think even if Cancellara required in excess of 900w, we can consider it attainable.

We've seen him accelerate like this and open up gaps that can't be closed many times before...

superb analysis! unfortunately like you wrote somewhere before, a motor can help u recover after a hard effort so ur power estimates can't really tell u if he used a motor or not. but 1000 watts is not out of the ordinary at all

Don't get me wrong, I like your post ..but seems to me like you're on a crusade to prove Cancellara didn't have a motor stuck up on his bike. Why not just wait a bit more to hear what they make of the investigation?

What personal gain do I have to go on a "crusade"? Thats very silly don't you think?

Anon @11:51 AM : The Gruber Assist comes from Austria. Rumor is that what is used on the pro bikes since 2004 comes from Hungary. There's no telling that like vials of EPO, they smuggle motors too these days across borders.

That analysis is all nice and dandy...but your neglecting some very important things. After bridging to the group initially Cancellara sits back on his saddle then surges again. You state that during this attack his rpm and gear ratio remain constant at 90rpm and an estimated 53-11. If his rpm is constant and the gear he's using doesn't change then how does he accelerate? The only way to increase his speed would be to increase his cadence but this doesnt happen during that 5sec span u focus on....this is what everyone says is so funny about the video: his apparent cadence and selected gear-ratio remain constant yet he accelerates nonetheless. Its the same deal with track cyclists: bc they ride fixed gears the only way to accelerate is to increase cadence...but like i just said Fabian's cadence appears to remain constant.

Ahh..Good catch. I think I know where you're confused about. Yes I was dum in not changing that RPM to 110 instead of 90. I didn't happen to use the cadence at all in my calculation for torque. It is likely he shifted to 53-11 before the attack and increased his RPM from 100 to 110 which is the way he accelerates. 110 seems about right from my stopwatch.

So yes as RPM changes, torque at the crank changes too. I'm going to change that last calculation on crank torque a bit and calculate it instead from his known cadence during the attack, which was around 110 RPM.

BRILLIANT stuff, TY so much for analysis on my favorite champion. I was arguing back n forth with A TOTAL imp on the forums, then showed him the page and managed to shut him up. World would be a better place without conspiracy theorists! How do people even think of utter BS like motor doping for a TT champ escapes me m8.

Oliver : LOL... I would like to clear my stance here though. I'm not saying its NOT possible to hide a motor in a bicycle. although I have expressed my doubts about its viability in the previous post. This post has little do with disproving that aspect. It is a mere analysis to show what Fabian was and is able to achieve on his bike specifically in a high intensity attack.

Hey Ron, great recap of both attacks during P-R and Flanders. I cant remember being so excited watching a race as when Cancellera drops Boonen on the Muur, wow! I recall discussing the attack with a buddy shortly after during a training ride, and how impressive the in-the-saddle move was, watching Boonen out of the saddle giving everything he has to hold Fabian's wheel, to no avail. In my mind Fabian is a hero, and I really hope that the accusations are all untrue. On the other hand, the Gruber assist is tempting for me and my weekend hammerfest (LOL). I recently tried First Endurance Pre Race (which worked really well for me), it's funny how even myself, not being a racer is looking for advantages over my buddys on training rides, so who knows? (pertaining to Spartacus and Floyd's numerous accusations)

Thank you very much for taking the time to comment. I don't think you need a motor unless you have physical challenges. The human body is built with its own amazing motor control and adaptation mechanisms. We have our own inbuilt CVT, and its free of charge. Building up the skill to ride or race your bike is not free however. It costs time and may even cost money, but its well worth the journey.

Not to take away from your work, but I would appreciate you edit away the snide comment against the Italian media. If you'd have done as much research into the youtube clip that "whistle blows" Cancellara's use of a motor in his bike as you'd done trying to disprove it, you'd realize that only the first part of the video showing the prototype of a motor in a bike comes from the Italian media. The theories against Cancellara are from your normal, everyday youtube uploader. The Italian media never once mentioned Cancellara in their part of the video, nor did they even allude to him or any other pro cyclist other than the one that provided them with the bike.

Anon @ 7:57 pm : I fully recognize that its the Youtube uploader who did this. However, I do not see a reason to edit what I wrote in the opening para. The rumor originated in Italy and what is perceived by many people, including me, is that journlists in the Italian cycling scene know what is going on.. I mean, who is this character Michele Bufalino? His name doesn't sound like Chinese to me. He's a video maker belonging to VideoNews TV Italy ofcourse!

To me, it is a whole lot more simple: Check out the other riders in the P-R attack. They practically stop pedaling, checking out each other, waiting, 'organizing', thinking up the next thing to do.

Fabian just got the perfect moment for an attack. That makes the speed difference as it seems for the camera huge. Anyone who has ever ridden a road race knows it: If you come up from the side, carrying speed and accelerating at the same moment the front of the peleton is holding back a bit, you explode from the front.

This is more about tactics, seizing the moment, the mental side of cycling than the physical side.

Anon @ 5:34 : Wattage = Voltage x Current. Its as simple as that. You know wattage, you know voltage, calculate current. For a motor to exist to have such power, these days you can purchase svelte units as this website catalogue for brushless DC motors will show you... http://www.teamnovak.com/products/brushless/motor_spec_chart.htm (890W motor weighs 10 ounches or 0.28 kg or 0.6 pounds)

But I don't think you can hide it easily in the downtube of a carbon fiber bike without some sort of telltale sign. The battery is going to be decently sized, I don't think a battery the size of your "sugar bag" exist to power such a motor.

You should read the post I wrote on Sunday, 31st of May. I explained it there.

At 49km to go Boonen took a rest. He had been throwing a lot at the pointy end of the race. The others except Cancellara took a rest as well. Can anyone guess how fast they were going at that point? They probably all felt a bit tired and slowed at the point Cancellara'sbrain saw the opportunity to attack. He went, they all looked at each other, bye bye. If they slowed to 40 km/h and he accelerated at thesame time to 55+km/h, that's a perfect launchpad for a man with his capabilities. A classic counter move. It was beautiful, but not that incredulous that he must have needed a motor. Anyone who's raced would know this.

Geographically the attack was correct, the road following was rough and narrow so anyone behind jockeying for position would lose time. It actually looked pretty obvious that Cancellara was discontented where he was in the middle of the group and should have been no surprise that he'd shoot off the front. I dont find the acceleration extraordinary, just that there was no-one on his tail. He probably just got pissed off with how slow everything was, felt good, so went hard. The other explanation does not involve motor asssist, but race rigging.

As much as the 'motor' might be a jest, it isn't really about race tactics, although there's no doubt that was well-timed. It's really about how effortless Cancellara made the attack look. The guy just took off without even getting off the saddle. It's even moreincredible that he later dropped Leukemans (he couldn't even keep up and waved his arm in frustration when he got dropped). BTW Leukemans got suspended a few years earlier for doping with artificial testosterone.

That combined with the Flanders Muur footage makes Cancellara look like superman/terminator.

I love cycling. Cancellara is a campeon that has made me enjoy many times. If this roumor was around when indurain was hamering all the tts, they will say he had a 200hp engien hide somewhere. I don't beleive the roumors and if by any chance they proove true, I will bin my bicycle and buy a motorcycle!!

This is just a comment to the hypothetical that someone did use an engine in a race: surely the benefit would not be in the attack, but in the conservation of energy prior to an attack? Was it a 45 minute battery pack? that's a hell of a lot of effort saved if it could be used effectively. while everyone else is putting in moderate to heavy effort to remain in the lead group, someone could be pottering along with an engine, using a fraction of the energy, and then be primed for a purely human-motor attack, relatively fresh.

All the discussion is interesting but one thing is missing that Cassani purposely left out. This thing requires a battery the size of a half loaf of bread and seems to have to sit under the saddle. It is so bulky, it cannot be attached anywhere else. In a televised, mega-photographed race, there is no way to hide the battery. Case closed. Even Gruber Assist now acknowledges it.

This is the total power to accelerate forward by the fact that I used Newton's law. Its an approximate number as I clearly mentioned in the post. Obviously, wind speed is a huge factor and the power needed would be 0.5 x density of air x frontal area x drag co-efficient x (relative wind speed)^2. I suppose the next component of power would be for rolling resistance, and grade of the road being ridden, etc but for this simple analysis, and since we don't know all those numbers to calculate these components of power, I neglect them. I really didn't intend to do a Master's thesis here.

In the last video from the "Tour de France", he is the only one to have his hands placed upside the brakes (see at 1:21 to 1:37, his two middle fingers are on the brakes... or suspected accelerator during the sprint!), all the other ones are sprinting with hands at the extremities of the handlebar.... why? May be the motor already existed in 2007. And I think he is smart enough to not do "impossible things" with his bike, or he would already have been caught long time ago... he just do it at the right time while staying inside physicaly possible limits.

Interesting analysis but it's not even as complicated as that. Watching the video from around 1m43 Cancellara is coasting; he moves smoothly to the left and gets on the wheel of the fourth rider who moves off the front. Up until he actually hits the gas he is hardly working at all and just hits it as the others are looking around. Perfectly executed attack, nothing mysterious about it.

What can you tell us about the existence of technology to boost or extend the output of a lithium battery, supposedly already in-use in motorsports (like F1)? Cyclingnews.com reports that Boardman warned the UCI that the technology required to motodope already exists:

"Speaking to the British newspaper Telegraph, Boardman said that in theory teams could use cutting-edge technology from Formula 1 to boost the power of any battery-powered motorized system. Boardman suggested they could even tap into the battery that was already used by several teams to power the front and gear changers on bikes." - http://is.gd/cGAWT

"I sat at a meeting with the UCI last year and drew on the blackboard exactly how this might work," Boardman told the Telegraph. "I showed them some of the sophisticated boosting technology now available, mainly from F1 teams, that can get a kilowatt out of a single AAA battery."-------------------------

So to motodope, what's the ultimate limiter? Is it the difficulty of fitting a motor into a carbon fiber frame?

Or the potential for noise-giveaway where the use of the motor is revealed by some telltale whine or other audible signal?

Or is Boardman wrong and the size/weight of the battery required to power a motodoping platform too great to make it viable for bike-use?

Looking forward to your thoughts on the batteries in particular, and motodoping limiters in general!

I read that article about Boardman and doubt whether he's seen what he's talking about. It seems to be like he's theorizing the possibility of someone using "F1 boosting" motors in the peloton. Besides, I question what this fancy "F1 boosting" technology is. Because if he's pertaining to automotive starter motors, they have been among us for quite sometime now. They can also be potentially used for "SHORT" high bursts of power, but they are pretty much useless in the long run because of temperature buildup, wear and tear in the motor brushes.

Sleek, powerful brushless DC motors are also used in RC airplanes, buggies, powerdrills etc. One particularly nifty motor is made by Tacon sold by Nitrocrx (http://www.nitrorcx.com/tacon.html)

See the technology surely exists for motors such as this but the limiter and Achilles heel of motors is the battery. The current chemical state-of-the-artness says Li polymer ions are the best as they pack the highest juice for weight. Hence, they are in laptops. They are expensive, die fast and could potentially be used for short term boost. That's all. Other possible materials for batteries that look promising is LiFePO4.

Conventional PMDC motors have been used for long in power assist electric bicycles. This is nothing new for them. In this area, hub motors are most preferred. Some of the cheap and durable solutions that exist are Crystalyte (http://www.crystalyte.com/pmdcc1fab.htm) , Currie motors etc but they are heavy for racing purposes.

If there is something out there that is being used for racing, I believe it is a brushless motor with an RPM no greater than 3600, combined with a battery that packs the most punch for its weight. It will be very expensive and not very durable.

I just want to say that in Italy we are not trying to defame Cancellara and his victory. Cancellara is really powerful and a great cyclist. However some of his 'surge' were 'strange' and incidentally the news about this engine came out. We hope there is nothing true in it. BTW, nice calculations.--Alberto

Thanks for the additional info, Ron. At this point I don't believe anyone is motodoping, but what a great story. I'm surprised that Specialized didn't come out w/ a "special" ad to poke fun at this story and be witty about Fabian and Specialized together = go like a moto or something.

Since every single fucking one of these riders eventually confess to doping, and the sport as a whole is nothing more than the cycling equivalent of the WWF, I am amazed that anyone even gives a shit whether he uses an engine or not. Why is one kind of cheating any worse than another? Just enjoy the races for the scenery, which is ultimately the only interesting thing about a "sport" where everyone cheats.

forget all of the math, just look at the fact there is not one ounce of strain, effort or increased RPM in some of the videos floating around. He takes off like a shot, but his RPMs don't change. When you out the hammer down like that, there is strain al over the body from arms, back and legs... he shows no effort just POW... and he is gone and his legs spin at the same RPM as they were moments before at the fraction of the speed.

As well, 1 of the questionable moves he did seated. You rarely, if ever, see a break away move done seated and done with such gapping. Attacks are almost always done standing for the instant power boost.

As well, in the recent Paris-Roubaix he takes off like a shot while the guy, who was leading, is working so hard, straining, and Cancellara just takes off with no real effort. The other guys legs and body are clearly crying out.. no seen effort by Cancellara.

He is strong, but not that strong. As well, hard to explain the hand and finger movements the others videos show he make moments before these extreme accelerations.

Having raced bikes for 20 years... nope, I don't buy it.. it clearly looks aided to me. Clearly. Everything in my body tells me that was not legit.

Nice job! A great read, you make things very understandable. However I found it hard to believe he attacked on 53-11 (a sprinters gear, normally used when the speed goes up to 65+km/h). So I put his crank length, tire dimensions etc into a gear calculator and got a speed of 56,6km/h for 100rpm and 62,2 for 110 rpm at 53-12. The same cadence on a 53-11 resulted in a speed between 61,7 and 67,9 km/h, so I think he probably rode the 53-12. This also is in line with Cancellara's incredible ability to spin (I recall reading the TT bike he used at the worlds last year had just a 12 as the smallest sprocket in the rear..)

For what it's worth, this was Tom Boonen's post-race comment in the Belgian media about the moment of Cancellara's attack: "We were doing 25 [km] per hour. Incidentally, when I came back to the front of the group, he had only 50 meters of an advantage. It wasn't decisive yet."

At the moment of the attack, Boonen was dropping back to the car, but it also looked like there was a considerable headwind. Therefore, your estimation of the group's and Cancellara's speed may be a bit on the high side.

Ironically, Boonen goes on to say about a moment in the race a little later on, when they were on a cobble section and the group chasing Cancellara had been reduced to eight: "If you work together for a little while, you can close a gap like that easily. Yes, also against Cancellara. There was a headwind, right? And there were eight of us. They didn't put a jet engine up the Switzer's ass either."

The "rumor mills of il Italia" comment strikes me as lazy, not only because "il Italia" is grammatically incorrect/meaningless, but because you don't substantiate your claim. I fully agree with anon. 7:57. If my name is Polish and I upload something nasty on youtube about Contador, does this mean there is a Polish conspiracy against Contador?

I understand that quite some care was taken in the analysis. However, from the video I find it hard to believe that the group of four were travelling at 49km/h when Cancellara accelerated. Sure, they had sped up somewhat from the snail's pace they'd been riding at just beforehand. But it was by no means a full blooded attack, and all four of them backed off quite soon, as Cancellara began moving forward. Two of the riders were looking around, and two of them stopped pedalling altogether for a time, one of whom to avoid running into the bloke in front.

The pedalling action of these four riders was certainly not purposeful.

You guys are getting too hung up on the numbers, and I told you not to in the post. Its all approximate, yes the measurement errors are in the range of 10%. Goodness, I was using a high school physics software and it is not technology from an earthquake laboratory.

Go take a break if Cancellara is tearing up your self esteem. And he did not use a motor, that is ridiculous. And for the umpteenth time, his RPM changed as he attacked! It was not constant. The next one who says RPM was constant will be deleted!

I just want to say that I don't believe it either as, from my calculations, he would need a power of 1200W. This is along the lines of your calculations, which means both of us are right. What I did is I calculated the torque (T = F * R, Force and wheel Radius) needed to ride with v=50Km/h and with an acceleration a=1m/s2; mass m=90Kg. These are all estimated but still, see the calculations below.So F=m*a=90*1=90N, T=F*R=90*0.33=29.7Nm.Now we calculated the RMP need for such a motor.omg=v/R=50km/h/0.33=13.8m/s2/0.33=41rad/s which means n=391rpm.So we need a motor wutg n=391rpm and torque T=29.7Nm or a geared motor with a total power of P=M*omg=1217.7W. Such a motor may exist but it'll not have the required torque.For example, the high RPM motors have a very small torque because, if they did have a high torque, we'd all had been using them.And if you take such a high RPM motor and gear it down to obtain high torque and small rpm you'll see that you'll need a very very small gear reduction system which, in my opinion, isn't going to fit there.

Nice analysis, but note: Cancellara was riding a Specialized Roubaix and not a Tarmac (mentioned in your calculation discussion section). The Roubaix has plastic plugs in the fork (called "Zertz" inserts by Specialized) and seat stays which behave like shock absorbers. The Tarmac does not have the inserts. The inserts were clearly visible in video footage of the race as Cancellara cruised solo toward the finish line. The wheelbase on the Roubaix is ~20mm longer than the Tarmac, but that isn't enough to bother changing your calculations.

A bit late to the discussion but I just wanted to give some props to the writter who did all the work in getting these calculations done. Brilliant job mate! As a fan of Cancellara, I'm clearly biased but I actually find it amusing how many variables people have come up with to try an justify attacking him... He didn't get out of the saddle... well, larger riders are more efficient in the saddle, particularly when they're TT specialists who know how to put the hammer down at full force without swinging the bike side to side under them. He 'shifts' his finger to the side... LOL, as someone who uses Red, what you're seeing is an upshift that's also clear in the momentary slowdown of his cadence before it comes back up and he accelerates away. He doesn't look like he's suffering... That's cause Spartacus doesn't show weakness, he just hammers. When someone's as consistantly excellent as Fabian, there will always be 'haters' out to diminish his accomplishments but the simple fact is, anyone who's followed Fabian over the years just isn't all that surprised by this kind of attack.

I appreciate the analysis and even though it is an interesting analysis it really isn't that complicated. After watching video from around 1m43 Cancellara is coasting; he just simply moves smoothly to the left and gets on the wheel of the fourth rider who moves off the front. At least up until he actually hits the gas he isn't really putting in much effort at all.

I found so many entertaining stuff in your blog, especially its discussion. From the tons of comments on your articles, I guess I am not the only one having all the enjoyment here! Keep up the good work.

I appreciate the analysis and even though it is an interesting analysis it really isn't that complicated. After watching video from around 1m43 Cancellara is coasting; he just simply moves smoothly to the left and gets on the wheel of the fourth rider who moves off the front. At least up until he actually hits the gas he isn't really putting in much effort at all.

Fabian Cancellara is a Swiss professional road bicycle racer for UCI ProTeam RadioShack-Nissan. A time trial specialist, he is a four-time World Time Trial Champion ... -phlebotomy programs in illinois